Blue Marble

The three-spined stickleback is a regulator of carbon dioxide emissions in its ecosystem: Piet Spaans (Viridiflavus) via Wikimedia Commons:

Top predators do more than regulate prey populations (think wolves and deer). They also regulate carbon dioxide emissions. At least they do in freshwater ecosystems—where if you take away the top predators CO₂ emissions rise a staggering 93 percent. 

This according to a new paper in the latest Nature Geoscience that holds ramifications for a lot more than marshes. "Predators are disappearing from our ecosystems at alarming rates because of hunting and fishing pressure and because of human induced changes to their habitats," said lead author Trisha Atwood, at the University of British Columbia.

I wrote in an earlier post here on research showing how the loss of biodiversity (itself often a function of the loss of top predators) likely alters CO₂ dynamics and other issues of global change as much as greenhouse gases.

The stonefly (Hesperoperla pacifica) whose presence helps keep CO₂ emissions in check: Lynette S. / Lynette Schimming via Flickr

Food web theory posits that predators influence the exchange of CO₂ between ecosystems and the atmosphere by altering processes like decomposition and primary production (a function of the numbers and diversity of plants).

To test that theory, the researchers experimented on three-tier food chains in experimental ponds, streams, and bromeliads in Canada and Costa Rica by removing or adding predators. Specifically by adding or removing three-spined stickleback fish (Gasterosteus aculeatus) and the invertebrate predators stoneflies (Hesperoperla pacifica) and damselflies (Mecistogaster modesta). When all the predators were removed the ecosystems emitted a whopping 93 percent more carbon dioxide to the atmosphere.

From the paper:

We monitored carbon dioxide fluxes along with prey and primary producer biomass. We found substantially reduced carbon dioxide emissions in the presence of predators in all systems, despite differences in predator type, hydrology, climatic region, ecological zone and level of in situ primary production. We also observed lower amounts of prey biomass and higher amounts of algal and detrital biomass in the presence of predators. We conclude that predators have the potential to markedly influence carbon dioxide dynamics in freshwater systems.

The paper:

• Trisha B. Atwood, Edd Hammill, Hamish S. Greig, Pavel Kratina, Jonathan B. Shurin, Diane S. Srivastava, John S. Richardson. Predator-induced reduction of freshwater carbon dioxide emissions. Nature Geoscience (2013). DOI:10.1038/ngeo1734

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Every two years, the Government Accountability Office—the independent agency charged with keeping an eye on how Congress spends our money—releases a list of programs and issues that present a high risk for fraud, waste, abuse, and mismanagement. This year, for the first time, the agency added climate change planning and response to the list—a reflection of the fact that the agency sees climate as a big fiscal risk for the US.

The GAO only added two new areas to its list this year that it believes creates risk. Climate change was one of them, along with the gaps in our weather satellite program. Here's how the GAO summed up the risks:

Limiting the Federal Government’s Fiscal Exposure by Better Managing Climate Change Risks. Climate change creates significant financial risks for the federal government, which owns extensive infrastructure, such as defense installations; insures property through the National Flood Insurance Program; and provides emergency aid in response to natural disasters. The federal government is not well positioned to address the fiscal exposure presented by climate change, and needs a government wide strategic approach with strong leadership to manage related risks.

Mitigating Gaps in Weather Satellite Data. Potential gaps in environmental satellite data beginning as early as 2014 and lasting as long as 53 months have led to concerns that future weather forecasts and warnings—including warnings of extreme events such as hurricanes, storm surges, and floods—will be less accurate and timely. A number of decisions are needed to ensure contingency and continuity plans can be implemented effectively.

On climate, the full report notes that the federal government was asked to pay out $60.4 billion in recovery funds for Hurricane Sandy alone. That's just part of an overall trend in increased disasters in the US that the GAO flags—including a record 98 disaster declarations in fiscal year 2011, up from 65 in 2004. The Federal Emergency Management Agency (FEMA) was on the hook for more than $80 billion in federal assistance between 2004 and 2011. And the federal government owns or insures a lot of at-risk property, in addition to managing 29 percent of the total land in the US.

The whole idea of the GAO list is to identify problem areas and try to fix them, so that we're not wasting money in the future. But the GAO notes that, since it started the list in 1990, only one-third of the issues it flagged have been addressed to the point that they could actually be removed from the list.

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United States Fish and Wildlife Service via Wikimedia Commons

A team of leading polar bear ecologists called for nations to make plans now for dealing with ongoing—and soon to be critical—threats to the survival of polar bears. The biggest problem for this iconic Arctic species is the mindblowingly fast disappearance of sea ice. Their paper appears in Conservation Letters.

For instance, last month (January 2013) the average coverage of sea ice in the Arctic Ocean was 409,000 square miles (1.06 million square kilometers) below the 1979 to 2000 January average. That's the sixth-lowest January extent in the satellite record, says the National Snow & Ice Data Center. Plus 2012 saw the lowest ever summer coverage of sea ice in the Arctic. 

The 19 polar bear populations identified by the IUCN: Andrew E. Derocher, et al, Conservation Letters (2013). DOI: 10.1111/conl.12009

It's not going to be easy to mitigate these challenges, the authors warn. There are 19 populations of polar bears worldwide. Some—like the Western Hudson Bay (WH, in the map above) bears and the Davis Strait (DS) bears—experience complete sea ice melt in summer that forces them onto land where they've got nothing to eat and can only burn through their own fat until the ocean refreezes.

For other populations—the Chukchi Sea (CS), Laptev Sea (LS), and Barents Sea (BS)—many bears remain on drifting pack ice and multiyear ice year round. The problem is that a lot of that pack ice is now retreating far beyond the continental shelf where ocean productivity is higher and polar bear prey more numerous. Meanwhile multiyear ice is disappearing rapidly throughout almost all the Arctic. 

Ansgar Walk via Wikimedia Commons

Here's what we know happens to bears forced ashore for too long in summer, or kept far offshore on multiyear ice:

• declines in body condition
• declines in body size
• declines in reproductive rates
• declines in survival rates
• declines in population size
• declines in sea ice denning habitat
• altered movements and distribution

How bad will it get? In an earlier paper one author predicted the extinction of polar bears in two thirds of their range by 2050. That's because low ice years will increase as long as greenhouse-gas-induced warming continues—until almost all years will be bad for polar bears. For example:

• Adult male mortality from starvation is predicted to increase to 28-48 percent in any year when the fasting period is 30 days longer than in recent years.
• The possible effects on other age and sex classes have not been modeled but are predicted to be more severe.
• Some years will continue to be better for polar bears and others poorer, even as the frequency of poor years increases until all are poor years.
• The first occurrences of exceptionally poor years are likely to present a near-term critical challenge to polar bear conservation.

The authors write:

When superimposed over the long-term declining trend, annual variability in sea ice makes it increasingly likely that we will soon see a year where sea ice availability for some polar bear populations is below thresholds for vital-rates. Malnutrition at previously unobserved scales may result in catastrophic population declines and numerous management challenges.

If you have the stomach for it, there's a desperately tragic video of a polar bear mother and her two cubs dying of starvation here. Be forewarned: this is graphic and ghastly. But it's also a sign of what's happening now and what's to come for many many more bears in the future. Knowledge of these kinds of events was one of the reasons this paper was written, lead author, and author of Polar Bears: A Complete Guide to their Biology and Behavior, Andrew Derocher told me.

Orphaned polar bear cubs being sent to a zoo: NOAA via Wikimedia Commons

It's not just about bears either. Starving bears forced ashore are already a threat to local communities and that's only likely to get worse in the near future. The authors write:

The most intensive program for dealing with human-bear interactions, the Polar Bear Alert program in Churchill, Manitoba, Canada, includes extensive hazing, relocation, and temporary housing of bears to mitigate conflict during the ice-free period. That program is expensive and may not be easily applied in small northern communities with limited resources. Nonetheless, we encourage alternatives to killing problem bears, which is a common outcome in northern communities. The Churchill program was established before the effects of climate change were recognized and it is unclear whether it will remain adequate as warming continues. Bears temporarily held in captivity are not currently fed so the cost of temporary holding will increase when the ice-free period extends beyond the fasting capacity of captive bears. Less-expensive options such as reducing attractants and securing storage of food should be included along with plans for increased deterrent capabilities. Training and equipping community polar bear monitors, along with extensive public education and inter-jurisdictional agreements, should be planned to help assure human safety.

Projections of cumulative months per decade where optimal polar bear habitat will be either lost (red) or gained (blue) from 2001–2010 to 2041–2050. Insets show average annual cumulative area of optimal habitat (right y-axis, line plot) for four 10-year periods in the 21st century (x-axis midpoints), and their associated percent. Larger version here: USGS

Derocher also pointed me towards this successful World Wildlife Fund Canada project to protect villagers from hungry, shore-bound bears in the Hamlet of Arviat, Nunavut.

Among the authors' other concerns:

• Polar bears are still hunted throughout the Arctic except in Norway and Russia. "Existing harvest management methods are inadequate for declining populations that, by definition, have no sustainable harvest."
• Feeding some bears might become necessary to keep people safe. "Diversionary feeding could be a viable short-term tool to draw bears away from settlements or industrial facilities." But possible negatives include: "the potential for disease and parasite transmission as well as human-wildlife conflicts may increase as other species such as Arctic fox, wolves, and grizzly bears are drawn into diversionary feeding locations​."
• Feeding might also be needed to keep bears alive in areas where they might not otherwise survive. [How sad is that?]
• Some bears might need to be sent to high-quality zoos for captive breeding.
• Some bears might need to be euthanized if they've starved beyond rehabilitation.

Stavenn via Wikimedia Commons

The authors conclude:

Considering the global attention paid to polar bears, managers will be forced to respond to sudden changes in environmental conditions that negatively affect polar bears. We believe that managers and policy makers who have anticipated the effects, consulted with stakeholders, defined conservation objectives, created enabling legislation, and considered possible management actions will be most able to effectively respond to large-scale negative changes.

Andrew Derocher told me: "One thing we try to make clear is that we don't necessarily recommend any of these options but lay them out for consideration and discussion. Further, we don't view these desperate measures as a replacement for dealing with greenhouse gasses.  If we don't deal with climate change we won't have any polar bear habitat left."

The paper:

• Andrew E. Derocher, Jon Aars, Steven C. Amstrup, Amy Cutting, Nick J. Lunn, Péter K. Molnár, Martyn E. Obbard, Ian Stirling, Gregory W. Thiemann, Dag Vongraven, Øystein Wiig, Geoffrey York. Rapid ecosystem change and polar bear conservation. Conservation Letters (2013). DOI:10.1111/conl.12009

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Weather forecasts predict that Snowstorm Nemo will be highly unusual in its intensity—the worst blizzard the Northeast has seen in ages. Already, thousands of flights have been canceled and people are scrambling to stock up on emergency supplies. So it might seem like now would be the perfect opportunity for the media to sound the alarm about the connection between climate change and extreme weather. But a new study finds that exactly the opposite is true: When it gets cold out, some prominent newspaper opinion writers start hammering out their next attempt to debunk global warming. 

Despite overwhelming scientific consensus about the long-term phenomenon, newspaper op-ed pages are most likely to opine about how climate change isn't real when seasonal temperatures dip. According to a new study published in Climatic Science, annual and seasonal deviations from mean temperatures can explain attitudes (both positive and negative) expressed in 2,166 opinion pieces between 1990 and 2009 in five major newspapers, the New York Times, Washington Post, Wall Street Journal, USA Today, and Houston Chronicle. (It also demonstrated that national public opinion polls aligned with temperature anomalies.)

During heat waves or temperature spikes, the percentage of newspaper columns that agreed with climate change rose. But when winters were rough or temperatures fell, the percentage of disagreement ratcheted up. Lead author and University of British Columbia climate scientist Simon Donner told Mother Jones it was difficult to explain such correlations, but he and his co-author took a stab at it, this way, in the paper:

Furthermore, editors may be more likely to write about climate change or to accept a submission on the subject during or after and [sic] anomalously warm season. Therefore, the relationship between climate variability and the opinion data may arise not solely from people viewing weather or climate anomalies as proof or disproof of climate change, but from the anomalies serving as a reminder of the issue of climate change and as “hooks” for opinion articles.

The problem with writing opinion articles supporting climate change exclusively during heat waves or slamming it during cooler seasons is that it fails to consider that the phenomenon is really "a long-term average," Donner says. "If next decade is warmer than this decade, it doesn't mean every day in next decade is warmer than every day in this decade. There's still going to be variability in the system."

If the public and newspapers are going to trust that climate change is real, even when it's cold outside, scientists and educators also have to step up and be more vocal. "We've got to talk about climate change not just when there's a good 'hook' to talking about it, but even you know, on unusually cold days in the summer," Donner adds.

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